I'm looking for some specific advice on compatibility of ham radioequipment, knowing next to nothing about HF radio stuff (working on ham license currently).

I'm considering purchasing an older ICOM 706MKIIG ham radio that comes with an LDG AT-7000 tuner. (The specified ICOM brand tuner for this radio is the AH 4.) The equipment is used on land in someone's ham "shack". Is it OK to use the LDG AT 7000 tuner for a boatinstallation?

I assume so, but thought I'd see if anyone familiar with this equipment had any specific knowledge on this. Related - are there specific antenna tuners from ICOM for use with their marine SSBs? (I know the 706 is not a marineSSB.) Just curious if there are separate tuners from ICOM for their marine radios.

The long answer is:
The AT-7000 (made by LDG) is a coax-output tuner, that is designed to provide a decent SWR to the radio when using resonant antennas slightly off from their resonance, and still allow the radio to see a good SWR...

This is not the type of antennas that are used for almost all marine HF installations (whether ham or maritime frequencies)...
We use end-end, random wire antennas, such as backstays, whips, wires, rope-tenna, "alt backstay antenna", etc...
And, as such, the tuner necessary for them is a remote, end-fed, autotuner....such as the Icom AH-3 / AH-4 (for ham radios) or Icom AT-130 / AT-140 (for marine radios)...

Also, understand that unlike the AT-7000, the AH-3/AH-4 and AT-130/AT-140 tuners are designed to be used not just in the "marine environment", but actually outdoors / out-in-the-weather, as they are "waterproof" and in UV-resistant cases...

So, all-in-all, the AT-7000 is a poor choice and will not work for our application...

Now, for the bad news...
My advice:

You'd be much better off buying an Icom M-700Pro marine radio and use this on both the ham radio bands and the maritime bands....
These sell for about $400 - $500....about the same or just a bit more than a good used IC-706MkIIG....and is head and shoulders, 10 times better of a radio than the IC-706!!!

I wrote this in another thread recently (see below for links):

Quote:

.... the horrible performance (both "on-channel" and "off-channel"/interference) that the typical HF ham radio exhibits when operated at "battery level voltages", must be understood!
Many/Most HF ham radios will simply NOT transmit (shut down completely or simply shut-down the transmitter) if the voltage supplied to them when transmitting is below 12.2 - 12.3vdc....and almost all exhibit distortions ("fm'ing", etc.)even with voltages of 12.3 to 12.6vdc, under transmit...and even if you get lucky, and have 12.6vdc or so at the radio when transmitting, most HF ham rigs will not output their full power or meet the spec's, at that lower voltage....as they are all designed for a clean/regulated 13.8vdc...

Remember that if your panel volt meter is showing 12.6vdc (a fully charged battery bank), and even if you have a direct battery connection for the radio, with correctly sized wire, a standard 3% voltage drop will give you 12.2vdc AT THE RADIO, when transmitting!!!
Ever wonder why you hear some guys running their diesel engines when on-the-radio?? A good rule-of-thumb is: If using an HF ham radio on-board, make sure you have at least 13vdc to 13.2vdc at the batteries, in order to allow the radio to work at all, and preferably 14.2 - 14.4vdc at the batteries, for peak performance!

The above contrasts with the real marine radios ("type-certified" HF maritime radios) such as the Icom's (M-700, M-700Pro, M-710, M-802), Furuno's, Sailor's, JRC's, Thrane, Skanti's, etc., which will work to their designed specs, throughout their specified operating voltage range...
In the case of the M-802, that is from ~ 11.5vdc to 15.5vdc...at the radio...full-power, no distortions, no interference!

[Also] Use of an inferior transmitter [typical ham radio], which has significantly worse transmit spectral purity than a "type certified" marine HF transceiver, DOES cause interference to other users of the Maritime HF channels/freqs...even if adjusted and operated "properly" and within the limits of it's "normal" operating parameters....(and with proper "13.8vdc")

...the venerable IC-706 has IMD products that look like a big fat Christmastree! with its 3rd, 5th, 7th, and 9th down only -31, -35, -40, -43...}What this means in the real world is that the (unknowing) user of the inferior transmitter, is causing interference to someone on an adjacent channel 20 to 40 times more severe / stronger than someone using a type certified marine transceiver.

(Of course, if you could fit the $1800 price into your budget, the Icom M-802 is your best choice...)

Jud, you're doing great, asking questions here....and know that I understand being on a budget, but please continue to do yourself a favor and do not spend any money on any radio / tuner, until you completely understand what your application is and what their particular abilities and interference problems will be...

Many thanks for the specific guidance on the AT 7000 antenna tuner - much appreciate that, as I didn't realize it wouldn't be appropriate for marine use.

And thanks a lot for reminding me about the voltage/operating requirements for ham vs. marine ssb radios. Totally makes sense when considering ham vs. marine ssb radio. On the other hand, one hears of many people using ham radios on boats, so I wonder how much of an issue this is.

Re: M-700Pro (ham radio), I was looking at M-710 (marine ssb), as I haven't seen the 700Pro for sale - but I understand from poking around on the web that the 710 (marine ssb) isn't the easiest to use on the ham bands outside of frequencies that you've programmed into the radio - i.e., you can't easily just "tune around" on ham bands. And, from what I gather --correct me if I'm wrong, I'm paraphrasing someone else -- an emergency situation is about only time people want to use the marine frequencies; all the maritime mobile nets are on the ham frequencies; and with few marine commercial stations, there is very little happening on the marine channels - all of which seems to suggests that a ham radio is far more useful (easier to use to get ham frequencies) than a marine ssb, where accessing ham frequencies is sort of a secondary function. Is that generally correct?

Thanks for your advice - greatly appreciated.
Jud

PS/I am aware of the ham vs. ssb legal issues and am aware the the Icom 802 is designed for easy use on marine and ham bands...but it's well out of my price range right now (as an aside, I've also heard, anecdotally, that the 802's compactness, like the earlier 706 ham radio, may render it prone to corrosion --the small space between components may have a tendency to trap salt/moisture, the downside of small radios?

Many thanks for the specific guidance on the AT 7000 antenna tuner - much appreciate that, as I didn't realize it wouldn't be appropriate for marine use.

And thanks a lot for reminding me about the voltage/operating requirements for ham vs. marine ssb radios. Totally makes sense when considering ham vs. marine ssb radio. On the other hand, one hears of many people using ham radios on boats, so I wonder how much of an issue this is.

Re: M-700Pro (ham radio), I was looking at M-710 (marine ssb), as I haven't seen the 700Pro for sale - but I understand from poking around on the web that the 710 (marine ssb) isn't the easiest to use on the ham bands outside of frequencies that you've programmed into the radio - i.e., you can't easily just "tune around" on ham bands. And, from what I gather --correct me if I'm wrong, I'm paraphrasing someone else -- an emergency situation is about only time people want to use the marine frequencies; all the maritime mobile nets are on the ham frequencies; and with few marine commercial stations, there is very little happening on the marine channels - all of which seems to suggests that a ham radio is far more useful (easier to use to get ham frequencies) than a marine ssb, where accessing ham frequencies is sort of a secondary function. Is that generally correct?

Thanks for your advice - greatly appreciated.
Jud

PS/I am aware of the ham vs. ssb legal issues and am aware the the Icom 802 is designed for easy use on marine and ham bands...but it's well out of my price range right now (as an aside, I've also heard, anecdotally, that the 802's compactness, like the earlier 706 ham radio, may render it prone to corrosion --the small space between components may have a tendency to trap salt/moisture, the downside of small radios?

Hmmm. I wouldnt consider the Icom M802 compactness as a negative in terms of corrosion.

We have both an Icom 735 (ham radio) and marine M710 (marine ssb) on board. We are OCD about all aspects of our equipment.

The 735 has significantly more noticeable exterior corrosion than the M710.

So I'm not supportive of your claim that compactness correlates with corrosion. Have you seen inside the units in question?

I knew I shouldn't have posted that stuff! ;-) I was simply passing along (1) info related to the 706 (someone I heard of had corrosion issues, which they correlated, correctly or not, to the compactness of the unit/proximity of components). And (2) re: 802, this was related to me today by a dealer; maybe just anecdote, maybe an actual case, I don't know.

I'm not claiming it's true or untrue, or know if component compactness in fact was the cause - I'm just relating what I've heard from what appeared to me knowledgeable sources.

BTW, out of curiosity, why do you have both ham and ssb (other than perhaps interest in radio)? I'm trying to decide between one or the other (used, and not an 802 - out of my budget). It would seem, based on what I posted above paraphrased from someone else, that a ham radio is the way to go in terms of ease of access to the ham bands you're most likely to access when cruising.

Other than being "marine grade" (not a trivial factor b/c of potential corrosion issues), I don't get the point of marine ssb when those radios are sometimes apparently rather inconvenient to use on ham bands (I'm excepting the 802, of course). Are the marine bands, in fact, frequently used when cruising, contrary to the opinion (of someone) that I posted in my post above? I'm really having a hard time deciding whether it makes sense to get a used ham or ssb radio. If one rarely accesses marine bands, I don't really understand the point of a (used, non-DSC) marine ssb.

Quote:

Originally Posted by leftbrainstuff

Hmmm. I wouldnt consider the Icom M802 compactness as a negative in terms of corrosion.

We have both an Icom 735 (ham radio) and marine M710 (marine ssb) on board. We are OCD about all aspects of our equipment.

The 735 has significantly more noticeable exterior corrosion than the M710.

So I'm not supportive of your claim that compactness correlates with corrosion. Have you seen inside the units in question?

Not sure where you heard that "all the maritime nets are on the ham bands". Not so. There are many maritime nets which function on the marine bands, including the daily Cruizheimers Net (8152 @ 0830 EST), Doo Dah Net (same frequency @ 1700 hours), CaribbeanSafety and Security Net, and many others.

While corrosion is always a problem in the marine environment, in many decades of working with and on both ham and marine radios on boats I've seen little evidence that ham radios -- compact or not -- are really more likely to corrode than are marine radios.

As I wrote in an earlier response to you, the principal difference between ham radios and marine "type certificated" radios is in the higher standard of performance, especially in their better suppression of unwanted emission products. Also, they are more tolerant of low voltage than are ham radios, and the IC706MKIIG -- a great little ham radio -- is the worst I've seen in this regard: with voltages much below about 12.4VDC it will badly distort (FM) and will even cut out completely. Whereas, any marine radio will work down to about 11VDC.

As John suggested, the Icom M700Pro is a fine radio out of the mold of the 710, and it even has a VFO of sorts. However, it's hard to find, especially for the price quoted. Usually, these go for $600-900 in my experience.

No question the M802 is highly desirable both because of its flexibility, inclusion of DSC capability, and voice quality on both receive and transmit. However, these are scarce on the used market and I'd be very careful buying a used one unless you know the seller and/or have real trust in the source.

And, believe it or not, this $1,800 marine radio is not even splashproof. Thanks, Icom :-)

You asked about why have both a ham radio and a marine radio. I have both, and believe that's a good solution for many. If you go used, you can find both radios in good condition for under $1,000.

Have used ham radios on boats for a good long time without any problems with low voltage affecting output or corrosion limiting their life span. Because of 12 straight days of overcast on my last passage battery voltage was getting just a little shy of 12v. The ICOM 718 Ham radio was still getting through with emails via the PactorModem and voice on the marine nets without an issue. Understand it is true that wattage output drops with lower battery voltage but they still worked fine. Someone explained that the difference between 100 watts and 80 watts is undetectable. Most of the cheaper ham radios like the 718 were designed for mobile use, that means battery power in many instances. If the reality of battery powered performance was as bad as speculated by John, they would be useless for general mobile use without generator or motor running. That is flat out not the case. Have talked regularly from Tahiti and all the way to Hawaii to California and points inland, South America and 'Down Under' with battery voltages less than fully charged. Fully charged batteries are 12.7v btw, well below what John claims the ham radios become useless. In reality voltages drops below 12.7v as soon as there is a draw based on my voltage meter.

FWIW, the ICOM 7200 Ham radio has all the front end moisture fighting features of the 802 Marine Radio. Not a super compact radio but easily hangs from a mobile bracket or sits on a shelf. Users have reported no issues with operating off of batteries on DXpeditions with heavy continuous use/draw on the batteries supplying power. It's a much newer design than the 718 and more complicated to operate if you want to take advantage of all it's features. Apparently it's being superseded by the 7300 but at a much higher price. Might be able to find one of these ham radios at under a $1000 new or even less used from one those people that has to have the latest and greatest if you wanted a more state of the art radio than the 718.

I'm sure the additional cost of Marine SSB's has more to do than just with printing 'marine' on the face plate but all SSB radio, whether Ham or Marine, pretty much work the same. Have even heard it rumored that the marine radios use some of the same circuit boards as the Ham radios.

Really appreciate all the detailed input, Bill. Very good food for thought.

BTW, the source of the opinion "all the maritime nets are on the ham bands"...was none other than Peter (roverhi), who I see just posted above. I should've linked to that in my post, but it seemed unnecessary. It was his post in a thread a few years back that got me really trying to put my finger on ham vs. ssb. Best Ham Radio Options

"Legally, you can't transmit on the marine frequencies EXCEPT in an emergency but that's the only time I'd want to use the Marine Frequencies. You'll find all the Maritime Mobile Nets, Email, etc on the Ham frequencies. With the demise of the Marine Commercial Stations, there very little happening on the Marine channels."

Which made start thinking, well, then why in the heck get a marine ssb? (except for the other considerations - built for marine environment; low voltage tolerance; low spurious emissions/good frequency stability, etc.) And lots of folks here and there on the web say the M-710, while a great marine ssb radio, and which I think I've found a very good deal on, is a bit of a hassle to use on ham bands --which is where, as I understood it, most if not all nets of interest to cruising sailors are anyway, so...why get a marine ssb (i.e., that one) ifnot convenient to use on ham bands?

Just trying to piece together in my mind the funky new world of radio-dom :-)

Quote:

Originally Posted by btrayfors

Not sure where you heard that "all the maritime nets are on the ham bands". Not so. There are many maritime nets which function on the marine bands, including the daily Cruizheimers Net (8152 @ 0830 EST), Doo Dah Net (same frequency @ 1700 hours), CaribbeanSafety and Security Net, and many others.

While corrosion is always a problem in the marine environment, in many decades of working with and on both ham and marine radios on boats I've seen little evidence that ham radios -- compact or not -- are really more likely to corrode than are marine radios.

As I wrote in an earlier response to you, the principal difference between ham radios and marine "type certificated" radios is in the higher standard of performance, especially in their better suppression of unwanted emission products. Also, they are more tolerant of low voltage than are ham radios, and the IC706MKIIG -- a great little ham radio -- is the worst I've seen in this regard: with voltages much below about 12.4VDC it will badly distort (FM) and will even cut out completely. Whereas, any marine radio will work down to about 11VDC.

As John suggested, the Icom M700Pro is a fine radio out of the mold of the 710, and it even has a VFO of sorts. However, it's hard to find, especially for the price quoted. Usually, these go for $600-900 in my experience.

No question the M802 is highly desirable both because of its flexibility, inclusion of DSC capability, and voice quality on both receive and transmit. However, these are scarce on the used market and I'd be very careful buying a used one unless you know the seller and/or have real trust in the source.

And, believe it or not, this $1,800 marine radio is not even splashproof. Thanks, Icom :-)

You asked about why have both a ham radio and a marine radio. I have both, and believe that's a good solution for many. If you go used, you can find both radios in good condition for under $1,000.

Great info, Peter. I remember, not very long ago, when I used to try to read these HF radio threads and my eyes glazed over...now they make a lot more sense. Really appreciate yours and Bill's (and others') clear explanations. Too often such threads seem to devolve into overly technical discussions or arguments!

Anyway, so it's a contest in my mind between the M-710 marine ssb (which it looks like I can get a really really good deal on, with tuner), or a newer 718 ham rig, which would give more ham flexibility (but probably cost more than the other good package deal with the M710). I can indeed see where, at some point, for redundancy/back up, one might want two radios.

It would be nice to be able to borrow radios to try them out, to see what it's like to access ham bands on the marine SSB, just to get a feel for it, never having used an HF radio.

Quote:

Originally Posted by roverhi

Have used ham radios on boats for a good long time without any problems with low voltage affecting output or corrosion limiting their life span. Because of 12 straight days of overcast on my last passage battery voltage was getting just a little shy of 12v. The ICOM 718 Ham radio was still getting through with emails via the PactorModem and voice on the marine nets without an issue. Understand it is true that wattage output drops with lower battery voltage but they still worked fine. Someone explained that the difference between 100 watts and 80 watts is undetectable. Most of the cheaper ham radios like the 718 were designed for mobile use, that means battery power in many instances. If the reality of battery powered performance was as bad as speculated by John, they would be useless for general mobile use without generator or motor running. That is flat out not the case. Have talked regularly from Tahiti and all the way to Hawaii to California and points inland, South America and 'Down Under' with battery voltages less than fully charged. Fully charged batteries are 12.7v btw, well below what John claims the ham radios become useless. In reality voltages drops below 12.7v as soon as there is a draw based on my voltage meter.

FWIW, the ICOM 7200 Ham radio has all the front end moisture fighting features of the 802 Marine Radio. Not a super compact radio but easily hangs from a mobile bracket or sits on a shelf. Users have reported no issues with operating off of batteries on DXpeditions with heavy continuous use/draw on the batteries supplying power. It's a much newer design than the 718 and more complicated to operate if you want to take advantage of all it's features. Apparently it's being superseded by the 7300 but at a much higher price. Might be able to find one of these ham radios at under a $1000 new or even less used from one those people that has to have the latest and greatest if you wanted a more state of the art radio than the 718.

I'm sure the additional cost of Marine SSB's has more to do than just with printing 'marine' on the face plate but all SSB radio, whether Ham or Marine, pretty much work the same. Have even heard it rumored that the marine radios use some of the same circuit boards as the Ham radios.

I can't comment re the suitability of the LDG tuner however......
I've had a 710 aboard for the last 20 years and a 706mk2G for 8 or 10 years....
Setup is 710/AT130/Backstay and 706/At 141/5 metre long whip.

On the last passage NZ to Chile I worked Tony's Net (EDIT New Zealand based ) daily throughout on 14315 ... started at their regular time ( 9am NZ time?) and then shifted to a 7pm NZ time to suit propagation and my watchkeeping.

So...started by using the 710 and a few days later did comparative testing between the two radios... unanamous verdict from the far side was that the 706 had far cleaner audio and better alround so stuck with that for the rest of the trip...last contact was within sight of the Chilean coast..still getting 5/6 reports. EDIT...and also working VK7s and VK2s who were outside the propagation window with 5/1 reception ( 5/0 on the 706 meter)
Used the 710 throughout for sailmail with no probs...from very early on working into Chile.
No probs with corrosion on either radio despite 10 of the last 12 years spent in the 'southern cone' and other southern 'high latitudes'

John and Bill (KA4WJA and WA6CCA), as always, provide sage advice. A few additional comments:

1) voltage matters, matters a lot! I strongly recommend EVERY boat with a ham radio aboard install a voltage booster. These will take boat voltages from 11 - 14 and put out a solid, regulated 13.8 that the radios need. They are a MUST in my opinion. The best are from TGE: TG Electronics

2) I have owned dozens of ham radios and several marine and commercial ones. John is, I regret, largely right about the poor suppression of harmonics in many new radios; indeed, the older ones are MUCH better (my own Icom 756 pro II one of the best). Used Kenwood, Icom, Thrane & Thrane, SEA, and (the rarer) Yaesu marine radios are better than almost any ham model on the market.

3) Don't skimp on the installation; do your research and test each element. Someday I really need to write a book on this to dispel all the bullsh*t that is published to boaters. Amateur and Military HF operators have had this stuff figured out for 100 years... it isn't black magic, just simple if detailed oriented RF engineering. Boaters should learn from the experts and not 'reinvent the wheel such as it is"

4) Whatever radio you choose; learn how to use it. Take a class; join a ham club; participate in 'Field Day' in June. Most radio issues (like any other boating ones) are those of presence (or lack) of skill and experience. And being a skilled radio operator is part of being a good cruiser (at least in my opinion)

5) Have fun. Radio is a great hobby totally independent of cruising... I love them both and having radio(s) aboard my cruising home make it safer and more fun.